Representation Index: This index measures the percentage of adult voters in a state who voted for the winning
candidate in House elections; it is determined by multiplying voter turnout in
U.S. House races by the percentage of votes cast for winning candidates.

Voter Turnout: The percentage of the voting eligible population
which voted in a state's U.S. House elections (as opposed to statewide
and presidential elections). We use population estimates by Professor
Michael McDonald at George Mason University. His figures estimate
the number of voting age adults who are eligible to vote, which means
they excludes non-citizens and ex-felons in states that disenfranchise
them.

Representation: This index measures the percentage of adult
voters in a state who voted for the winning candidate in House
elections; it is determined by multiplying voter turnout in U.S. House
races by the percentage of votes cast for winning candidates.

Landslide Index: Percentage of all races won by at least 20%

Margin of Victory: The winner's percentage of all votes cast minus the second-place candidate's percentage

Seats-to-Votes Distortion: The seats-to votes distortion
measures the extent to which one party wins a greater percentage of
seats than votes and the other party wins a smaller percentage of seats
than votes. You add the percentage distortion for each party and
divide by two. For example, if Democrats won 10% more seats than
votes and Republicans 6% fewer seats than votes, the distortion would
be 8.0%.

Democracy Index: A state's average ranking in key categories:
average margin of victory (measuring overall competitiveness),
landslide index(measuring number of somewhat competitive races),
seats-to-votes distortion(measuring how well the intent of voters was
reflected by results) and representation index (weighted double, as it
measures both voter participation and the percentage of effective votes
that elect someone)